A coordinate measuring device of the type mentioned in the introduction comprises a base which defines an upright axis, a support, and a telescope unit for emitting a measurement beam and for receiving at least a part of the measurement radiation reflected at a target. The orientation of the telescope unit is carried out in two axes (upright axis or vertical axis, and inclination axis or tilt axis) by means of motors. The support can be swiveled in a motorized fashion about the upright axis relative to the base, and the telescope unit can be swiveled in a motorized fashion about a tilt axis relative to the support. A measurement axis is defined by an emission direction of the measurement radiation.
The telescope unit is equipped with opto-electro-mechanical components and is mounted, rotatably by means of a shaft about the tilt axis, at one or two bearing positions on the support, which is optionally likewise equipped with opto-electro-mechanical components.
WO 2007/079600 A1 discloses, with a laser tracker, such a laser-based coordinate measuring device having a telescope unit which can be rotated with respect to at least two axes and in which light emission and light reception optics of the distance measuring apparatus, a measurement camera and a viewfinder camera are arranged. The telescope element is mounted, rotatably about a tilt axis, on a support element, and the support element is mounted, rotatably about an upright axis, on a stationary base.
In coordinate measuring devices of the type mentioned in the introduction, which are known from the prior art, a shaft is respectively mounted fixed on both sides along the tilt axis and/or the upright axis. If, as is generally usual, different materials are used for the shaft, bearing or support, the clamping of the bearing varies as a function of the working temperature range. The flow of force which results from the clamping of the bearing of the tilt axis is transmitted via the brace of the support to the tilt axis. Hysteresis effects detrimentally affect the accuracy of the coordinate measuring device.
Radial displacement of the axes, for example by bearing air, in this case leads to accuracy losses.